When Yale University student Molly Clark-Barol got the invitation, she was reluctant to go. A naked party? Where people stand around without any clothes on? It sounded way too awkward.
But she decided to check it out and says she found the experience "kind of liberating."
"It was really low key, kind of just like any other party," says Clark-Barol. "Except you're naked."
Yale is one of several Ivy League schools at which naked parties are part of the campus culture. Ask the partygoers why they attend and they may tell you something about releasing academic pressure, self-expression or experimentation.
But push them a bit more and you'll find that when you put 30 or so naked college kids together in a room, the pulse of youthful rebellion runs strong.
A Tradition of Nudity
Most parties at Yale begin with a cryptic invitation, like this one recently sent to a Yale student:
"You are invited to a Party this Hallow's Eve. Meet on Cross Campus…at 11, 11:30, Midnight…The location will be revealed, as will you."
Held late in the evening, the parties are usually a last stop after an evening of social revelry. Full of liquid courage, the naked partygoers check their coats -- and their clothes -- at the door. The guest lists for the smaller parties are usually limited to around 30 or 40 people, and the conversations tend to be more intellectual, partygoers claim.
And there are strict rules about touching and gawking. If guests start getting too friendly with each other, they're asked to leave.
"It's more about breaking taboos," says Clark-Barol. "You feel more like running around in circles than hooking up with someone."
The tradition of naked parties at Yale is not new. In the 1990s, a naked party held in a small campus dining area called the Buttery was dubbed, "Nude Night at the Butt." Also in the late 1990s, a secret society called "Porn 'n Chicken," met together to watch pornographic movies while eating fried chicken in the nude, sources tell ABCNEWS.com.
The club gained national attention after its leaders threatened to make their own pornographic movie starring Yale students. Though the film was never released, in 2002, Comedy Central produced a fictionalized TV movie depicting the club's activities.
The prevalence of naked parties on college campuses is not only a Yale phenomenon -- the university shares a certain national notoriety for the tradition with its fellow Ivy, Brown University, according to Luke Skurman, CEO of College Prowler, Inc., a company that produces "insider" guides written by students for over 230 colleges.
A student society on the Yale campus called "The Pundits" is famous for the several naked parties it hosts each year, but it members like to keep their identities anonymous. They don't want the Yale administration to know who they are.
But the Yale administration seems to stay away from the parties, as long as they are "safe."
"Yale trusts its students, we give them a lot of latitude and independence," says Gila Reinstein, a spokesperson for the university. "We don't intervene with their social lives or their extracurricular activities."
Taking off Clothes, Blowing off Steam
Experts say that like the streakers of the 1970s, naked partyers at college are after self-expression and stress relief.
"In college you see a lot of experimentation," said Dr. Sandra L. Coren, author of "Sex Matters for College Students: Sex FAQs in Human Sexuality." "They're making a statement about being free."
At Harvard, where students gather in the famed Harvard Yard for a "primal scream" and a naked lap during finals week, public nudity is a form of stress relief.
"People in these kinds of institutions experience lots of stress and they try to release it," says Dr. Richard Kadison, Chief of Mental Health Services at Harvard. Put a bunch of diverse students together and turn up the academic heat, and students need a way to release the pressure. "Sexual experimentation is one way."
Tarnishing Ivy League Images?
Baring it all at a naked party can have its consequences, however. Ivy leaguers with Ivy League ambitions don't want public sexual acts or nudity tarnishing their future professional -- or political -- careers.
Vladimir Djuric, a recent Harvard graduate who worked for "H Bomb," a campus sex magazine launched last year, said that many classmates steered away from public nudity.
"A lot of people at Harvard have strong political ambitions," Djuric told ABCNews.com. "If they were photographed naked at a naked party, that would hamper any chance at a bid for political office in the future."
But at larger parties, things can run amok. At Brown, smaller naked parties are often held on an "invite-only" basis in student housing, just like at Yale. But a couple of times each year, the school's Queer Alliance throws a "SexPowerGod" party that is attended by hundreds of people and where nudity is encouraged and sex acts often take place. Last year, a Fox News reporter bought a ticket to the party online; in the footage from the story, individual faces of students were clearly visible.
Many students were outraged, and the party has since taken more discreet measures to ensure people outside of the student body are not admitted.
At Princeton, a long tradition of streaking on campus used to culminate at a yearly "Nude Olympics" in which up to 350 students gathered to play sports in the buff. But faced with reports of public sex and urination and alcohol poisoning by participants, the university banned the event in 1999.
Rumors of public nudity on Ivy League campuses have even touched the first family. Cartoonist Gary Trudeau, who went to Yale with President George W. Bush, wrote his first ever cartoon for the Yale Daily News about allegations that the president's fraternity made incoming members bare their backsides to be branded by a coat hanger.
And the rumor that President Bush's daughter, Barbara, might have attended a naked party during her time at Yale prompted Hustler magazine published Larry Flynt to offer a $1 million reward for any evidence that might exist. So far, he hasn't had any takers.
Other Ivy League groups hold events that overtly lean towards the sexual. At Columbia University, an S&M club called Conversio Virium "attempts to promote and support…safe, sane and consensual BDSM play," according to its Web site. While its stresses that the group meets only for discussion and listening, a report by the New York Daily News last year described one meeting in which a female student volunteered to be flogged with a leather whip and rubber hoses.
As for Yale, attendees maintain that the parties are safe. When Yale's Clark-Barol lost her clothes in a naked party clothes check, she had a "panic attack" until her friends came to the rescue, lending her a few articles of clothing before walking her back to her room.